The present invention relates to catalyst compositions suitable for olefinic polymerization and to methods of forming polyolefinic products using the subject catalyst composition. More particularly, the present invention is directed to heterogeneous catalyst composition comprising a cation component derived from at least one bidentate or tridentate transition metal compound which is activated by an ionic metal or metalloid, silane-modified inorganic oxide support, as fully described herein below. The subject compositions have been found useful in catalyzing olefinic and acetylenic polymerization to provide high molecular weight homopolymers and functionalized copolymers.
Ziegler-Natta and metallocene-alumoxane type catalyst systems are well known in the art as being useful for the polymerization of olefins. Recently, metallocene ionic-pair type of catalyst has been developed which can provide polymer products having improved properties compared to conventional catalyst systems. PA1 Ziegler-Natta type catalysts have long been the conventional system used in olefinic polymerization processes. The transition metal catalyst and the activator (e.g., trialkyl aluminum) may be introduced into the reaction zone on a support. These supports are normally inorganic oxides. Silica, as a support for Ziegler-Natta type catalysts, has been widely used in commercial polyethylene processes, as described in Macromol. Symp., 1995, 89, 563. PA1 T represents an inorganic oxide core support such as silica, alumina, preferably a silica macromolecular core, where a portion of the precursor inorganic oxide has hydroxyl groups pendent therefrom; PA1 SiR'R" represents a silane bridging group in which each R' and R" independently is selected from hydrogen, a C.sub.1 -C.sub.20 hydrocarbyl, or a C.sub.1 -C.sub.20 hydrocarbyloxy group and Si is a silicon atom; PA1 D represents an unsubstituted C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 hydrocarbylene group, or a substituted C.sub.1 to C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 hydrocarbylene, including a C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 hydrocarbylenoxy group, a C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 fluorinated hydrocarbylenoxy group or a C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 fluorinated hydrocarbylenoxy group. The above groups can be selected from alkylene, cycloalkylene, arylene, polyarylene, or fused arylene groups which may be unsubstituted or be fluorinated or be substituted by one or more alkyl, alkoxy, or aryl groups. D preferably represents a sterically bulky hydrocarbylene or fluorinated hydrocarbylene group such as a branched alkylene, a cycloalkylene, an arylene (unsubstituted or having one or more alkyl substitution groups), a fluoroarylene group, a polyarylene (unsubstituted or having one or more alkyl substitution groups) or a fused arylene group (unsubstituted or having one or more alkyl substitution groups) or the like. The most preferred D groups are unsubstituted or substituted arylene, polyarylene or fused arylene groups; PA1 M represents an atom of boron, aluminum, gallium, indium or tellurium in its +3 oxidation state and mixtures of the foregoing, preferably bo1ron or aluminum and most preferably boron; PA1 Q each independently represents a C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15, substituted or unsubstituted hydrocarbyl, or a C.sub.1 to C.sub.20, preferably a C.sub.4 to C.sub.20, more preferably a C.sub.6 to C.sub.15 substituted hydrocarbyl, including C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 hydrocarbyloxy, C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 fluorinated hydrocarbyl or C.sub.1 -C.sub.20, preferably C.sub.4 to C.sub.20, more preferably C.sub.6 to C.sub.15 fluorinated hydrocarbyloxy group. Each Q may be, for example, an alkyl, aryl, alkaryl or aralkyl group or an alkoxy, alkoxyaryl or aralkoxy group wherein the alkyl and aryl portions thereof are as described above. The preferred Q are those which are perfluorinated groups described above and most preferably a perfluorinated aryl, alkaryl or aralkyl group; PA1 O represents oxygen; PA1 Ct is the Precursor Cation and represents a cationic group capable of forming a neutral salt with the Precursor Anion material, preferably a remnant of a Br.o slashed.nsted acid; and PA1 each y, x, n and m represents an integer such that the ratio of the product of (m times x) to the product of (n times y) is one. PA1 Me=CH.sub.3 --; Et=CH.sub.3 CH.sub.2 --; Ph=phenyl; --C.sub.6 --H.sub.4 --=phenylene; --C.sub.10 H.sub.6 --=naphthylene; C.sub.6 F.sub.4 =tetrafluorophenylene; C.sub.10 F.sub.6 =hexafluoronaphthylene; C.sub.6 F.sub.5 =perfluorophenyl. PA1 (a) [N,N-dimethylaninilium] PA1 (b) [triphenyl carbonium] PA1 (c) [tropyllium] PA1 (d) [Ferrocinium] PA1 (e) [Ag.sup.+ ] PA1 (f) [K.sup.+ ] PA1 each A independently represents an oxygen, sulfur, phosphorous or nitrogen and preferably represents oxygen or nitrogen or a combination thereof and most preferably each A in III and at least two A's of IV represent nitrogen; PA1 Z represents at least one Group IV or VII transition metal selected from Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt in the +2 oxidation state or Ti, Zr, Hf in the +2, +3 or +4 oxidation states, preferably a late transition metal selected from iron, cobalt, nickel or palladium and most preferably iron or cobalt; and PA1 each L independently represents an anionic ligand group selected from the group consisting of hydrogen, halo, and hydrocarbyl. More specifically, the hydrocarbyl group can be substituted or unsubstituted, cyclic or non-cyclic, linear or branched, aliphatic, aromatic, or mixed aliphatic and aromatic including hydrocarbylene, hydrocarbyloxy, hydrocarbyl, silyl, hydrocarbyl amino, and hydrocarbyl siloxy radicals having up to 50 non-hydrogen atoms. The preferred L groups are independently selected from halo, hydrocarbyl, and substituted hydrocarbyl radicals. The hydrocarbyl radical may contain from 1 to 20 carbon atoms, preferably from 1 to 12 carbon atoms and the substitution group is preferably a halogen atom. In certain instances there may be three (3) L groups covalently bonded to Z. However, this is not preferred. PA1 R.sup.3 and R.sup.6 of IIIa or R.sup.6 of IIIb are each independently selected from an unsubstituted or substituted C.sub.1 -C.sub.20, preferably C.sub.3 -C.sub.20 hydrocarbyl, such as alkyl, aryl, alkaryl or aralkyl group as, for example, i-propyl, t-butyl, 2,6-dilsopropylphenyl, their flourinated derivatives and the like, or with adjacent groups, together, may represent a C.sub.3 -C.sub.20 hydrocarbylene group. Further, it is understood that in those instances where a hetero atom A (e.g., oxygen, nitrogen) of a bidentate compound has only a single covalent bond to the hydrocarbylene moiety of said compound, the hetero atom has an additional R group bonded thereto and such R group is independently selected from the above groups represented by R.sup.3 ; PA1 R.sup.4 and R.sup.5 are each independently selected from hydrogen, an unsubstituted or substituted C.sub.1 -C.sub.20 hydrocarbyl such as an alkyl, aryl, alkaryl or aralkyl group as, for example, methyl, ethyl, i-propyl, butyl (all isomers), phenyl, toluyl, 2,6-diisopropyl phenyl and the like; or R.sup.4 and R.sup.5 taken together provide an unsubstituted or substituted C.sub.3 -C.sub.20 ring forming hydrocarbylene group, such as hexylene, 1,8-naphthylene and the like. PA1 Z and each L are as defined above. It is preferred that Z be selected from nickel or palladium and that each L be independently selected from chlorine, bromine, iodine or a C.sub.1 -C.sub.8 (more preferably C.sub.1 -C.sub.4) alkyl. PA1 R.sup.7 and R.sup.8 are each independently selected from an unsubstituted or substituted aryl group wherein said subtitution is an alkyl or a functional group which is inert with respect to the contemplated polymerization; PA1 R.sup.9 and R.sup.10 are each independently selected from hydrogen, an unsubstituted or substituted C.sub.1 -C.sub.20 (preferably C.sub.1 -C.sub.6) hydrocarbyl as, for example, alkyl (methyl, ethyl, propyl, pentyl and the like); aryl (phenyl, toluyl and the like) or a functional group which is inert with respect to the polymerization (e.g., nitro, halo and the like); PA1 R.sup.11, R.sup.12, and R.sup.13 are each independently selected from hydrogen, an unsubstituted or substituted C.sub.1 -C.sub.20 hydrocarbyl or an inert functional group, all as described above for R.sup.9 ; PA1 Further, it is understood that in those instances where a hetero atom A (e.g., oxygen, nitrogen) of a tridentate compound has only a single covalent bond to the hydrocarbylene moiety of said compound, the hetero atom has an additional R group bonded thereto and such R group is independently selected from the above groups represented by R.sup.9 ; PA1 Z is a transition metal, preferably Fe(II) or Fe(III); and PA1 each L is independently selected from a halogen such as chlorine, bromine, iodine or a C.sub.1 -C.sub.8 (preferably C.sub.1 -C.sub.5) alkyl or both L groups, together in combination, represent an unsubstituted or substituted, saturated or unsaturated, hydrocarbylene group which together with Z forms a cyclic group, preferably a 3 to 7, most preferably 3 to 5 member ring cyclic group. PA1 Cat represents the Cationic Component derived from the transition metal bidentate compound III and/or tridentate compound IV wherein only one L group is pendent from the transition metal atom thereof; PA1 "n" and "m" represent integers; PA1 "a" and "b" represent integers of 1, 2 or 3 such that the product of (a) times (n) is substantially equal (e.g., .+-.10%) to the product of (b) times (m); and PA1 Si,R',R",O,D,M,Q, and T, each have the same definition as described with respect to formula I above.
Over the past decade, single-site olefin polymerization catalyst systems have been developed. These systems typically use a Group IV-B metallocene compound (compounds having at least one cyclodienyl group coordinated by the pi-bond to a transition metal as, for example cyclopentadienyl and bis(cyclopentadienyl) transition metal compounds) and an ionic activator. U.S. Pat. No. 5,241,025 teaches the use of a catalyst system comprising a Group III-A element compound. This compound has a cation capable of donating a proton which irreversibly reacts with a ligand of the Group IV-B metal compound and an anion which is bulky and non-coordinatable with the Group IV transition metal cation produced upon the reaction of the metallocene and activator compound. Similarly, U.S. Pat. No. 5,198,401 teaches that ionic catalyst compositions can be prepared by combining two components, bis(cyclopentadienyl) Group IV-B metal complex containing at least one ligand which will combine irreversibly with the second component or at least a portion thereof such as a cation portion thereof. The combination of the two components produces an ionic catalyst composition comprising a cationic bis(cyclopentadienyl) Group IV-B metal complex which has a formal coordination number 3 and a 4+ valence charge and the aforementioned non-coordinating anion. Both of the above U.S. Patents are directed to homogeneous metallocene polyolefin catalyst systems. Use of these catalyst systems in slurry reactors, can result in reactor fouling, poor productivities, poor polymer bulk densities, and poor polymer morphologies.
A supported ion pair catalyst system is taught in WO 94/03506. The support, which had been modified with an alkyl aluminum reagent, is treated with a solution of a metallocene catalyst and an anionic activator, and the solvent is removed. The resulting catalyst system provided a heterogeneous ion pair catalyst system of low activity. This system is taught to be useful in slurry reaction processes. Such processes are highly desired as they combine the advantages of homogeneous catalysis and the ease of particle forming associated with slurry and heterogeneous polymerization processes. However, because there is no direct chemical bond between the catalyst ion pair and the support, resolubilization of the catalyst is possible and would cause the system to be unsuitable for slurry reaction processes.
Activators which are widely used are aluminum compounds selected from an alumoxane or an aluminum compound having the formula AlR.sub.3 wherein each R is independently selected from a C.sub.1 -C.sub.20 hydrocarbyl or C.sub.1 -C.sub.20 hydrocarbyloxy group and preferably selected from alumoxanes and tris(C.sub.1 -C.sub.4 hydrocarbyl) aluminum compounds. The alumoxanes are most preferred. These compounds are oligimers or polymeric aluminum oxy compounds containing chains of alternating aluminum and oxygen atoms and whereby the aluminum atoms carry a substituent such as an alkyl group. Alumoxanes are normally formed by the reaction of water and an aluminum alkyl, which may, in addition to the alkyl group, contain halide or alkoxide groups, as disclosed in U.S. Pat. No. 4,542,119 and EP-A-338,044. The most preferred alumoxane is methylalumoxane (MAO). Due to the unstable and pyrophoric nature of alumoxanes, one must use a high degree of care in handling systems using these activators.
More recently, several patents (U.S. Pat. Nos. 5,516,737; 5,529,965; 5,595,950; and 5,625,015) disclose the use of silica supported metallocene/aluminum alkyl activated systems for slurry and gas phase heterogeneous olefin polymerization processes. However, these systems, like others which use MAO and the like as activator, have known disadvantages of requiring high molar ratios of aluminum to metallocene in order to achieve a catalyst composition of suitable reactivity, although such systems still produce undesirable low molecular weight polymer product.
WO 93/11172 discloses the use of certain polyanionic transition metal catalyst compositions. The anionic moiety is composed of a plurality of metal or metalloid atom containing non-coordinating anionic groups which are chemically bonded to a core component, such as silica, via a hydrocarbyl moiety. The transition metal catalyst is generally of the metallocene type. This catalyst system has certain disadvantages. Firstly, the anionic metal or metalloid component is taught to be bonded to the support substrate by dehydrohalogenation of a halogen containing metal/metalloid precursor with hydroxyl groups of the support. Small amounts of halogen by-product and/or precursor remain in the product. These materials can poison the catalyst system. Further, the reference teaches that the metalloid precursors, 4, 5 and 6 (See FIG. 1 of WO '172) may be reacted with the hydroxylated substrate, such as silica, alumina or metal oxide to bond the metalloid to the substrate. This produces an equivalence of HCl which may be liberated or produce an ammonium halide which will poison the resultant catalyst system and, thereby, achieves a system of low activity. Still further, the reference teaches that the support should be made substantially free of residual hydroxyl groups which are known to be located on the silica surface. Such groups are also known to reduce the activity of the intended catalyst. Removal of all of the hydroxyl groups is difficult. Still further, WO 93/11172 teaches that one must avoid exposing its catalyst to high concentrations of functional (especially oxygen containing functional) groups as such groups can poison the catalyst system. Finally, the catalyst system taught by WO 93/11172 and WO 97/19959 has low catalytic activity, is sensitive to oxygen and oxygen containing groups and provides polymer products having low polydispersity (narrow molecular weight distribution). Polymer products having these properties are difficult to process (e.g., extrude) by known techniques.
It would be desirable to provide a heterogeneous catalyst composition and a polymerization process capable of producing olefinic polymers at good catalyst efficiencies. It would be further desirable to provide a heterogeneous catalyst composition suitable for use in slurry and heterogeneous gas phase polymerization processes. Still further, it would be desirable to provide a heterogeneous catalyst composition capable of producing olefinic polymers having a sufficiently high polydispersity value, that is, to provide a polymer product of desired broad molecular weight distribution and of high weight average molecular weight. Still further, it would be desirable to provide a heterogeneous catalyst composition which is substantially free of halogen atom containing materials. Finally, it would be desirable to provide a heterogeneous catalyst composition capable of producing olefinic polymers from comonomers, some of which comprise oxygen atom containing functional groups.